librsb 1.3.0.2

Functions
backsolve.c File Reference
Example programs and code

C triangular solve example program. Uses rsb_spsv(),rsb_tune_spsm(). Based on <rsb.h>. More...

## Functions
int | main (const int argc, char *const argv[])

## Detailed Description

C triangular solve example program. Uses rsb_spsv(),rsb_tune_spsm(). Based on <rsb.h>.

Author
  Michele Martone

/*
Copyright (C) 2008-2021 Michele Martone
This file is part of librsb.
librsb is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
librsb is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public
License along with librsb; see the file COPYING.
If not, see <http://www.gnu.org/licenses/>.
*/
/*!
\ingroup rsb_doc_examples
@file
@author Michele Martone
@brief A first "hello RSB" example C program based on <rsb.h>.
Uses #rsb_lib_set_opt(), #rsb_mtx_get_info_str().
\include hello.c
*/
#include <rsb.h> /* librsb header to include */
#include <stdio.h> /* printf() */
int main(const int argc, char * const argv[])
{
/*!
A Hello-RSB program.
This program shows how to use the rsb.h interface correctly to:
- initialize the library using #rsb_lib_init()
- set library options using #rsb_lib_set_opt()
- revert such changes
- allocate (build) a single sparse matrix in the RSB format
using #rsb_mtx_alloc_from_coo_const()
- prints information obtained via #rsb_mtx_get_info_str()
- multiply the matrix times a vector using #rsb_spmv()
- deallocate the matrix using #rsb_mtx_free()
- finalize the library using #rsb_lib_exit()
In this example, we use #RSB_DEFAULT_TYPE as matrix type.
This type depends on what was configured at library build time.
* */
const rsb_blk_idx_t bs = RSB_DEFAULT_BLOCKING;
const rsb_blk_idx_t brA = bs, bcA = bs;
const RSB_DEFAULT_TYPE one = 1;
const rsb_type_t typecode = RSB_NUMERICAL_TYPE_DEFAULT;
const rsb_nnz_idx_t nnzA = 4; /* matrix nonzeroes count */
const rsb_coo_idx_t nrA = 3; /* matrix rows count */
const rsb_coo_idx_t ncA = 3; /* matrix columns count */
/* nonzero row indices coordinates: */
const rsb_coo_idx_t IA[] = {0,1,2,2};
/* nonzero column indices coordinates: */
const rsb_coo_idx_t JA[] = {0,1,2,2};
const RSB_DEFAULT_TYPE VA[] = {11,22,32,1};/* values of nonzeroes */
RSB_DEFAULT_TYPE X[] = { 0, 0, 0 }; /* X vector's array */
const RSB_DEFAULT_TYPE B[] = { -1, -2, -5 }; /* B vector's array */
char ib[200];
struct rsb_mtx_t *mtxAp = NULL; /* matrix structure pointer */
rsb_err_t errval = RSB_ERR_NO_ERROR;
printf("Hello, RSB!\n");
printf("Initializing the library...\n");
if((errval = rsb_lib_init(RSB_NULL_INIT_OPTIONS)) !=
RSB_ERR_NO_ERROR)
{
printf("Error initializing the library!\n");
goto err;
}
printf("Correctly initialized the library.\n");
printf("Attempting to set the"
" RSB_IO_WANT_EXTRA_VERBOSE_INTERFACE library option.\n");
{
rsb_int_t evi=1;
/* Setting a single optional library parameter. */
errval = rsb_lib_set_opt(
RSB_IO_WANT_EXTRA_VERBOSE_INTERFACE, &evi);
if(errval != RSB_ERR_NO_ERROR)
{
char errbuf[256];
rsb_strerror_r(errval,&errbuf[0],sizeof(errbuf));
printf("Failed setting the"
" RSB_IO_WANT_EXTRA_VERBOSE_INTERFACE"
" library option (reason string:\n%s).\n",errbuf);
if(errval&RSB_ERRS_UNSUPPORTED_FEATURES)
{
printf("This error may be safely ignored.\n");
}
else
{
printf("Some unexpected error occurred!\n");
goto err;
}
}
else
{
printf("Setting back the "
"RSB_IO_WANT_EXTRA_VERBOSE_INTERFACE"
" library option.\n");
evi = 0;
errval = rsb_lib_set_opt(RSB_IO_WANT_EXTRA_VERBOSE_INTERFACE,
&evi);
errval = RSB_ERR_NO_ERROR;
}
}
mtxAp = rsb_mtx_alloc_from_coo_const(
VA,IA,JA,nnzA,typecode,nrA,ncA,brA,bcA,
RSB_FLAG_NOFLAGS /* default format will be chosen */
|RSB_FLAG_DUPLICATES_SUM/* duplicates will be summed */
,&errval);
if((!mtxAp) || (errval != RSB_ERR_NO_ERROR))
{
printf("Error while allocating the matrix!\n");
goto err;
}
printf("Correctly allocated a matrix.\n");
printf("Summary information of the matrix:\n");
/* print out the matrix summary information */
rsb_mtx_get_info_str(mtxAp,"RSB_MIF_MATRIX_INFO__TO__CHAR_P",
ib,sizeof(ib));
printf("%s",ib);
printf("\n");
if((errval =
rsb_spmv(RSB_TRANSPOSITION_N,&one,mtxAp,B,1,&one,X,1))
!= RSB_ERR_NO_ERROR )
{
printf("Error performing a multiplication!\n");
goto err;
}
printf("Correctly performed a SPMV.\n");
rsb_mtx_free(mtxAp);
printf("Correctly freed the matrix.\n");
if((errval = rsb_lib_exit(RSB_NULL_EXIT_OPTIONS))
!= RSB_ERR_NO_ERROR)
{
printf("Error finalizing the library!\n");
goto err;
}
printf("Correctly finalized the library.\n");
printf("Program terminating with no error.\n");
return EXIT_SUCCESS;
err:
rsb_perror(NULL,errval);
printf("Program terminating with error.\n");
return EXIT_FAILURE;
}

## Function Documentation

## ◆ main()

int main | ( | const int | argc,
|  | char *const | argv[]
| ) |  |

A Hello-RSB program.

This program shows how to use the rsb.h interface correctly to:

- initialize the library using rsb_lib_init()
- allocate (build) a single sparse matrix in the RSB format using rsb_mtx_alloc_from_coo_const(), with implicit diagonal
- print information obtained via rsb_mtx_get_info_str()
- multiply the triangular matrix using rsb_spmv()
- autotune the matrix for rsb_spsv with rsb_tune_spsm()
- solve the triangular system using rsb_spsv()
- deallocate the matrix using rsb_mtx_free()
- finalize the library using rsb_lib_exit()

In this example, we use RSB_DEFAULT_TYPE as matrix type. This type depends on what was configured at library build time.